Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.
It is known to provide steel in coils. Such coils are formed around a central bore. The coils are typically stored on palettes with the bores vertical. A circumferential steel strap and usually four radial coil straps are provided to ensure the integrity of the coil as it is handled. The mechanical properties of such coils are explained in the paper Lifting of Steel coils in Bore-Vertical Orientation, by C. V. Tu and W. Y. D. Yen, presented at the 5th Australasian Congress on Applied Mechanics (ACAM 2007 10-12 Dec. 2007, Brisbane, Australia). As explained in that paper, such coils are usually handled by a lifting device that includes a mechanism to allow lifting feet to penetrate the bore and extend outwards under the inner wraps of the coil before lifting. However, coil telescoping has been known to occur during such lifting whereby the coil straps break so that the coil suddenly unwraps itself in an elevated position.
It will be realized that such coil telescoping presents a dangerous situation to workers and is time consuming to remedy.
It is an object of the present invention to provide an improved vertical coil lifter that addresses the above described problem and is an improvement, or at least a useful alternative, to lifters of the prior art.